1. Field of the Invention
This invention relates to gas tanks and, more particularly, to the fabrication of a gas tank for motorcycles.
2. Description of the Prior Art
There are primarily two types of gas tanks for motorcycles, one fabricated from aluminum and a second fabricated from steel. The gas tanks, regardless of what material they are made out of, are typically formed or stamped and then welded together. Typically, prior art gas tanks have been lap welded. Prior to the present invention, hydroforming techniques have not been used in fabricating motorcycle gas tanks. Different fabricating approaches are used, depending on a particular motorcycle chassis that the tank will be fitted to. The tanks include a tunnel area which receives part of the motorcycle chassis. This tunnel area may present structural and fabrication problems. Prior art gas tanks may be susceptible to vibration and cracking, which results in gasoline leaking from the tank, and this may result in fire problems.
Another problem is simply the structural strength of the tank is important, such as in case of an accident where the tank may break, with the resulting loss of gasoline and the potential for fire.
Welding techniques of the prior art typically use continuous beads and lap welds. This results in heat problems and ultimately results in structural problems in the tanks.
The method of the present invention overcomes the problems of prior art motorcycle gas tanks. Heavier gauge steel is used in the present method, and the specific steps outlined provide a gas tank for a motorcycle which is strong and which may be adapted to different types of motorcycle chassis. Butt welds are used, and the butt welds are stitch welded.
The invention described and claimed herein comprises a method for making a gas tank for a motorcycle which includes a series of steps beginning with the forming of two halves by hydroforming techniques. The two halves are butted together and tack welded prior to being stitch welded. A reinforcing plate is welded inside the tank at the juncture of the two halves after a bottom tunnel portion is cut from the joined halves. The resulting gas tank is structurally strong.
Among the objects of the present invention are the following:
To provide a new and useful method of making a gas tank;
To provide a new and useful method of making a gas tank for a motorcycle;
To provide a new and useful method of making a gas tank for a motorcycle by hydroforming two tank halves;
To provide a new and useful method of making a gas tank for a motorcycle by stitch welding butted tank halves;
To provide a new and useful method of making a double tank unit including a gas tank and an oil tank; and
To provide a new and useful method of forming and welding a motorcycle gas tank.